New pesticidal compounds and methods of making same



Unite States 3,047,459 NEW PESTICIDAL COMPUUNDS AND METHQDS OF MAKING SAME Mario Perini, Milan, and Giovanni Speroni, Florence, Italy, assignors to Montecatini-Societa Generale per IIndustria Mineraria e Ch'irnica, Milan, Italy, a corporation of Italy No Drawing. Filed Nov. 8, 1955, Ser. No. 545,779 Claims priority, application Italy Nov. 9, 1954 Claims. (Cl. 167-22) The present invention relates to new pesticidal compounds and to the methods of making these compounds. More particularly, the invention relates to thiophosphoric esters of the general formula wherein X represents oxygen or sulphur, R represents lower alkyls, and R represents a saturated straight or branched-chain alkyl.

The products according to the present invention are prepared by reacting a phosphate of the general formula RiO\ X RIO/ SY wherein Y is an alkali or alkali-earth metal or ammonium, with an ester of a halogen-substituted acetic acid of the general formula hal--CH -COOR Where R has the afore-stated meaning and hal is a halogen (C1 or Br).

A characteristic example of this synthesis is given by the following reaction in which sodium QO-diethyldithiophosphate is reacted with ethyl chloro-acetate to yield the ethyl ester of 0,0-diethyldithiophosphoryl-acetic acid:

CaHsO SNa The reaction occurs with high yields in the presence of a solvent for one or both reactants.

The following can be used as solvents: mouohydric aliphatic alcohols, ketones, aliphatic esters, dioxane, aromatic hydrocarbons (such as benzene, toluene and xylene). The reaction is carried out at a temperature between 10 and 150 C. A modification of the process consists in using, instead of the salt of the acid, the acid itself and a metal salt such as Na CO K CO BaCO NaOH or KOH, which is sufiiciently alkaline. We found that'the compounds of the present invention possess decided insecticidal properties and that some are equal and even superior to prior insecticides, such as Parathion. Moreover, these insecticidal properties are coupled with a relatively low toxicity to warm-blooded animals.

Example 1 of absolute ethanol.

is separated 'from the aqueous layer by means of a separatory funnel and washed repeatedly with water and a saturated solution of Nal-ICO The oily product is then dried over MgSO and distilled under vacuum: 42.3 g. of a straw-colored oil are obtained, having a 1311 122 c.

The analysis of the product is in agreement with the formula (C H O) PSSCH COOCH Example 2 The sodium salt of 40.9 g. of diethyldithiophosphoric acid is formed by treating with 4.95 g. of Na in 100 cc.

Then, 24.5 g. of ethyl chloroacetate are added and, after the mixture has been stirred at room temperature for 11 hour, the alcohol is distilled oil on a water bath until the reaction mass reaches a temperature of C. The residue is cooled to room temperature and filtered to remove the sodium chloride. The filtrate is shaken several times with water and with a NaHCO solution; then it is dried over MgSO and distilled under vacuum. 43.7 g. of a straw-colored oil are obtained, having a RP. 110-112 C.

The analysis of the product is in agreement with the formula (C l-I 0 PSSCH -COOC H Example 3 The sodium salt of 29 g. of dimethyldithiophosphoric acid is formed by treating with 4 g. of Na in 70 cc. of absolute methyl alcohol. Then, 18 g. of methyl chloroacetate are added and, after the mixture has been left standing at room temperature for 14 hours, the methyl alcohol is removed by distillation at normal pressure. After cooling, =l00 cc. of water are added to the mass to dissolve the NaCl formed. The undissolved oil, separated in a separatory funnel, is first treated repeatedly with water and a saturated NaHCO solution, and then dried over MgSO and distilled under vacuum. 21 g. of' a colorless oil are obtained, having a B.P. 110 C.

The analysis of the product is in agreement with the formula (CH O PSSCH COOCH Example 4 A salt is formed between 35.3 g. of dimethyldithiophosphoric acid and 5 g. of Na in cc. of methyl alcohol. Then 135.3 g. of ethyl chloroacetate are added and, after standing overnight and after removal of the methyl alcoholat reduced pressure, 50 cc. of water are added to the residue. The oil is extracted with CCL; and this solution shaken several times. with saturated, aqueous NaHCO The solution is then dried over Na SQ, and distilled under vacuum. After removal of the solvent and of the tops, 21.55 g. of a colorless oil are collected, having a B.P. 1l0-l13 C.

The analysis of the product is in agreement with the formula (CH O) PSSCH COOC H Example 5 KCl that formed. The oil fraction is separated from the aqueous solution, shaken several times with water and arr mass C with a N-aHCO solution, and is then dried over MgSO and distilled under vacuum. 32 g. of a straw-colored oil are thus obtained, having a B.P. 120-l21 C.

The analysis of the product is in agreement with the formula: (C H O POSCH COOC H Example 6 34 g. of potassium salt of diethylthiophosphorie acid are reacted in the presence of 70 cc. of acetone (partial solution) with 22.5 g. of n-butyl chloroacetate. After standing overnight at room temperature, the solvent is distilled ofi and, after cooling, 40 cc. of water are added to dissolve KCl that formed. The oil fraction is separated from the aqueous solution, shaken with water and with The analysis of the product corresponds with the formula (C H O PSSCH COOC H (i).

The products described in the examples have been used as insecticides on Musca domestica, on Aphis fabae and on T etranycltus telarius in parallel experiments with Parathion, a known insecticide. The results of these tests are indicated in the following table:

Musca domestica Aphz's fabae Tetranychus telarz'us tarsal contact topical application Spraying Spraying Product Concen- Active Active tration, Mortality, Dose, Mortality, substance Mortality, substance Mortality, gJm. percent 'y/fiy percent $233511- percent eggtciegilpercent 0. 0002 100 0. 08 100 0. 01 100 0. O1 100 Parathlon 100005 50 0. 01 45 0.001 75 0.001 8 Methyl dlethyldithio-phospho- 0 005 100 0. 4 100 0. 1 98 0. 1 98 Ylacetate 0 005 54 1 88 0, 02 4 0. 02 37 Ehtyl diethyldlthio-phospho- 0 005 100 2 100 rylacetate 0:001 27 Q4 66 75 100 Isobutyl dlethyldithiophospho- 0 008 100 2 100 0 5 100 0 1 100 rylacetate of 002 20 0, 4 71 0,1 40 0. 02 75 Methyl dlmethyldithiophospho- .2 a a a a Ethyl diethylthlophosphorylacetate 0.005 100 3 100 96g 33 2g n-Butyl dlethylthiophosphorylacetate 0. 005 100 3 100 Isoamyl diethylthlophosphorylacetate 0.005 100 3 1 22 22 Ethyl dimethyldithiophosphorylacetate 96%: 8g 32 65 a NaHCO solution, dried over MgSO and distilled under vacuum.

33.4 g. of a straw-colored oil are obtained, having a B.P. 13s -140 c.

The analysis of the product is in agreement with the formula (C H O) POSCH COOC H (n).

Example 7 34 g. of potassium salt of diethylthiophosphoric acid are reacted in the presence of 70 cc. of acetone with 2.4.6 of isoamyl chloroacetate. After standing overnight, the solvent is distilled off at reduced pressure by heating on a water bath and, after cooling, cc. of water are added to dissolve KCl that formed. The oil fraction is separated from the aqueous solution, shaken with a N aHCO solution and Water and, after vacuum distillation, 34 g. of a straw-colored oil are obtained, having a B.P. 143- 145 C.

The analysis of the product corresponds with the formula ((2 1-1 0) POSCH -COOC H (i) Example 8 29 g. of pure diethyldithiophosphoric acid dissloved in 70 cc. of acetone are neutralized with 8.5 g. of anhydrous sodium carbonate. After the carbonate is dissolved, 22 g. of isobutyl chloroacetate are added. The mixture is refluxed for 3 hours and the solvent is distilled at normal pressure on a water bath. After cooling, the residue is The herein-disclosed products are only moderately toxic o to warm-blooded animals, as indicated by the experimental data collected in the following table, and based on the toxicity of Parathion as a standard. Of the described products, the derivatives of dithiophosphorylacetic acid show the lowest toxicity.

Acute toxicity upon intravenous and oral administrations, expressed in thing/kg. as DL on mice, 24 hours after administration.

The herein disclosed compounds may be used as such as insecticides or fungicides, or one or several of them may be admixed with other known pesticides, such as insecticides and/or fungicides and applied as solidsor in form of solutions or dispersions in inert vehicles. Moreover, these compounds may be employed in conjunction with plant nutrients and fertilizers.

We claim:

1. As new pesticides, thiophosphoric acid esters of the general formula 1? RO SGH2COOR wherein X is taken from the group consisting of oxygen and sulphur, R represents lower alkyls and R represents a member of the group consisting of lower straight and branched-chain alkyls.

2. As a new pesticide, the methyl ester of 0,0-diethyldithiophosphoryl-acetic acid.

3. As a new pesticide, the isobutyl ester of 0,0-diethyldithiophosphoryl-acetic acid.

4. As a new pesticide, the methyl ester of 0,0-dimethyldithiophosphoryl-acetic acid.

5. As a new pesticide, the ethyl ester of 0,0-dimethyldithiophosphoryl-acetic acid.

6. As a new pesticide, the ethyl ester of 0,0-diethylthiophopsphoryl-acetic acid.

7. As a new pesticide, the n-butyl ester of 0,0-diethylthiophosphoryl-acetic acid.

8. As a new pesticide, the isoamyl ester of 0,0-diethylthiophosphoryl-acetic acid.

9. In the art of controlling a pest, the improvement comprising applying to the locale of the pest, a thiophosphoric acid ester of the general formula 1? RO/ \SCH2-COOR wherein X is taken from the group consisting of oxygen and sulphur, R represents lower alkyls and R represents a member of the group consisting of lower straight and branched-chain alkyls.

10. The invention defined in claim 9, the pest being taken from the group consisting of M usca domestica, Aphis fabae, and T etranychus telarius.

11. The invention defined in claim 9 in which X is sulphur.

12. In the art of controlling a pest comprising a member of the group consisting of Musca domestica, Aphis fabae, and Tetranychus zelarius, the improvement comprising applying to the locale of the pest the ethyl ester of 0,0-diethyldithiophosphoryl-acetic acid.

13. A thiophosphoric acid ester of the formula CHgCO-O 0111;

s 002115 ll/ s1 OCzH:

14. A thiophosphoric acid ester of the formula:

CH2-COOR lsVoR SP\ in which the R groups represent lower alkyl radicals.

15. A thiophosphoric acid ester of the formula:

CHPCOOR g!) OR in which the R groups represent lower alkyl radicals.

References Cited in the file of this patent UNITED STATES PATENTS 2,266,514 Romieux et a1 Dec. 16, 1941 2,494,284 Cassaday et a1 Jan. 10, 1950 2,645,657 Rudel et a1 July 14, 1953 2,802,856 Norman et al. Aug. 13, 1957 OTHER REFERENCES Kosolapotf: Chemical Abstracts, vol. 48, pp. 6639- 6640, 9902-9903 (1954). 

1. AS NEW PESTICIDES, THIOPHOSPHORIC ACID ESTERS OF THE GENERAL FORMULA 